Colored



Dec. 92, 1933. P, BROSSE 1,939,939

i COLORED FILTER Filed Feb. 24, 1928 Fig/ lnvEnTOR'- Zz w] B19/055W mitm@ ATTORNEY Patented Dec. 12, 1933 gagg stares f COLORED FILTER Paul Brosse, Neuilly, France, assignor, by mesne assignments, to Kislyn Corporation, New York, N. Y., a corporation of Delaware y Application February 24, 1928, Serial No. 256,643,

' and in France February 28, 1927 4 Claims. (Cl. 95-8L5) Tinted gelatine color lms, as used for the prodistribute over the whole surface of the iilm to jection of goilered films, oier two characteristic be projected the beams that pass through them. definitions: In Fig. 3, R is again the red tube, V the green 1. They fail to distribute color uniformly over tube and B the blue tube. Tube R is shown 5 the whole lm surface and have to be combined connected with a thermo-Siphon device S, which, with a system of prisms or of cylindrical lenses indeed, should be separately applied to each one in order to give their full eiect; l of the three tubes in order to permit the liquids 2. Their coloring fades very quickly. t0 cool. In the case where the tubes are plunged The object of my invention is to overcome this v into a liquid, the latter is what there would be octowfold deficiency Whenever a system of lters casion to cool by means of the thermo-Siphon de- 65 is to be intercalated between'the source of light vice. and the goiered film in a line;` such lm being 'I'he mineral salts to be used (in aqueous soluof the type in which a linear goffering is utilized. tion) foreach one of the liquid screens may vary. My invention is characterized by the use of I will indicate, as examples, the following ones:

UNET

v colored salt solutions arranged in or circulated For red:

through juxtapositioned cylindrical tubes inter- 1. 10% chromic acid solution with chloride of 70 posed in the path of the light beam passing from cobalt added, or

the condenser to the film. Due to the breaking or 2. 1/1000 chameleon mineral with red chrosplitting-up action that is exerted on light by a mate of potash added.

tube filled with a liquid having anindex of re- For green: 75 fraction different from. that of the medium 3. 50% nitrate of copper with red chromate of wherein the tube stands (air, for instance), each potash added. l screen-tube will operate rst after the manner For blue: 4. 1% Celestial liquor (nitrate of of a short-focussed cylindrical lens. copper and diluted ammonia) or 2.5 In the accompanying drawing, Figure 1 is a 5. Nitrate ofcopper up to saturation with sul- 80 sectional view of the invention taken in a direcphate of chromium added. tion perpendicular to the lter tubes; Fig. 2 is a Solutions 1, 3 and 4 are especially suitable.

View of a modification in which the tubes are Where projection is to be electuated with illl immersed in a tank lled with liquid; and Fig. ters arranged between the lm and the camera, Y 3 is a fragmental diagrammatic perspective view, solutions enclosed in cylindrical tubes cannot be 85 on an enlarged scale, showing the projection used; but the solutions can be introduced into from the tubes in a direction parallel'with the juxtaposed parallel-faced tanks without the optical axis. sharpness of the projection being impaired.

It will be apparentl from Fig. l that the beam L I claim as my invention: passing through each tube becomes spread over 1. A polychrome lter for projecting goffered 90 the whole surface of the goffered lm F to be lms in colors, comprising a plurality of lenses illuminated. On the other hand, owing to the formed of transparent hollow elements disposed fact that the colors are those of the salt solutions in xed position immediately adjacent one anthemselves, the coloring of the filters will not be -other in the path of the light rays and containing 40 liable to fade. different colored liquids corresponding to the col- 95 The red, green and blue tubes, in Fig. 1, conors t0 be projected. taining solutions of the corresponding colors. 2. A polychrome filter for projecting goered are designated R, V and B, respectively; and lms in colors, comprising a plurality of lenses in the modification illustrated in Fig. 2, the same formed of transparent hollow elements disposed reference characters are employed to indicate the in xed DGSibiOn immediately .adjacent 011e an- 100 tubes of the same colors as before, while L likeother in the path of the light rays and containing wise indicates the light beams and F the film. solutions of diierent colored salts corresponding In the latter case, however, the tubes are imto the colors to be projected. y mersed in aparallel-faced tank T which is filled 3. A polychrome filter for projecting goil'eredwith a liquid having an index of refraction diffilms in colors, comprising a transparent, rpar- 105 ferent (and, preferably, higher) than that of allel-faced tank containing liquid, andaplurality the liquids with which the tubes are lled: for of transparent tubular elements immersed in the instance, certain chlorides of carbon, the-tetratank liquid and situated immediately adjacent chloride, for example. In this case the tubes will one another in the path of the light rays; said act as diversing cylindrical lenses. and will again tubular. elements containingr different colored 11oy 2 v liquids having a refraction index lower than that of the tank liquid and corresponding to the colors to be projected.

4. In combination, a goffered film subjected to a. beam of light, a polychome lter in xed position relative to said lm and comprising a plurality of cylindrical lenses parallel to each other PAUL BROSSE. 

